Testing appliance.



R. sTRAUBEL. TESTING APPLIANCE AYPLIOATION FILED IEB.3, 1910.

Patented June 21, 1910.

z I l UNITED STATES PATENT OFFICE.

BUDOLF S'IBAUBEL, OF JENA, GERMANY, ABSIGZNOR TO THE FIRM-OI CARL ZEIBS,013 JENA, GERMANY.

TESTING- APPLIANCE.

Specification of Letters Patent.

Patented June 21, 1910.

To all whom it may concem:

Be it known that I, Rnnonr SmnpsL, a citizen of the German Empire,residing at Carl-Zeiss-Strasse, Jena, in the Grand Duchy of Saxe-Weimar,Germany, have invented a new and useful Testing Appliance, of which thefollowing is a spec1fication.

The invention relates to testing appliances which are used in ordnancefor ascertaim ing, whether the sighting device is so ad usted that theline of sight is in its zero position parallel to the bore axis of thegun. It is an im rovement on a. well known appliance, which consists ofa collimator adapted to be inserted in the with its collective lensdirected tower the barrel mouth and with the collimator axis parallel tothe bore axis, and a mirror system de signed to be placed before thatmouth. Th s mirror system has separate entrance and exit openings andpresents a fixed angle of deflection of 180. When the distance betweenthe said openings is equal to the distance between the gun sightingdevice and the collimator inserted in the barrel, the distant mark imageprojected by the collimator and reflected by the suitably located mirrorsystem will be seen to lie in the line of sight, provided that thesighting device is correctly adjusted to its zero position.

The object of the invention is to provide a mirror system, in which thedistance between the entrance and the exit opening can be varied atwill, for the purpose that the appliance can be employed, for instance,in ordnance having two sighting devices at different distances from thebarrel. The novel mirror system consists of two or more partial systemsrotatably connected in consecutive order with the exit opening of onepartial system facing the entrance opening of the other, one artialsystem deflecting the collimator axis y 180 and the other or thetotality of the other ones deflecting it by zero, elfecting thus only aparallel displacement of this axis.

As a mirror system deflecting by 180 such a one is to be preferred whichconsists of a plane mirror and a right-angled double mirror bothconnected in such a manner that the rid e line of the double mirror isperpendicu or to the plane of the plane mirror. This mirror s stem issuperior to other ones likewise de acting by 180, for

example, to a mere ri ht-anglcd double mirror, since it reflects al ofthe entering rays in a direction parallel to that of entrance, not onlythose rays incident within the principal plane of reflection. Thereforeit need not, as the other systems, be adjusted, so that the collimatoraxis enters within the principal lane of reflection. This s 5- tem issuitaby realized by two isosce es right-angled prisms, one of which hasa plane, the other one a ridge hypotenusal surface.

The mirror system deflecting b zero is preferably composed of two simp ereflectingisosceles right-angled prisms connected together with parallelhypotenusal surfaces. Such a system likewise need not be adjusted,so'that the collimator axis enters within the principal plane ofreflection.

The figure of the annexed drawing is a longitudinal section through agun, its sighting device and an appliance fitted to the gun andconstructed according to the invention.

The new appliance is combined with a gun barrel a, to which a sightingtelescope 5 serves as the sighting device. The telescope is presumed tohave been adjusted to the zero position in the vertical as well as inthe horizontal plane. N ow it is to be tested, whether the line of sightof the telescope be parallel to the bore axis of the gun. The collimatorinserted into the gun,barrel is supposed to consist of two parts. Acasing c is fitted in the chamber of the barrel a and carries crosswires 0, the crossing pointof which serves as the mark of thecollimator, and further, for illuminating the cross wires, a mirror 0which receives light from the sky. A second casing (l is fitted in themouth of the barrel and carries the collective lens d of the collimator.This lens as well as the cross wires are arran ed centrally in theircasings, so that the co limator axis is not merel parallel to, butcoincides with, the bore axis of the barrel a. The casing d moreovercarries one of the partial mllIOI systems. This first partial system isformed by two isosceles rightan led prisms, a ridge rism e and a simp lerefiiectmg pnsui j. T e other partial mirror system is formed b twosimple reflectin prisms g and g. ts casing k is oined wit the casing dat the point where t e entrance prism g of the hinder partial system andthe exit prism f of the front partial system face each other. By meansof this joint, the casing it can be rotated about the section of thecollimator axis lying between the prisms f and g so as to adjust thedistance between the entrance and exit openings of the total mirrorsystem.

I claim:

1. An appliance for testin the sighting device of a gun, consisting o? acollimator, which comprises a collective lens and a mark placed in thefocal plane of the lens this collimator being adapted to be inserted inthe un with'the collective lens directed to ward the barrel mouth andwith the collimator axis parallel to the bore axis, and a mirror systemcomposed of two partial systems having separate entrance and exitopenings and being rotatably jointed together with the exit opening ofone partial system and the entrance opening of the other facing eachother, the angle of deflection of one partial system bein 180 and thatof the other partial system ing zero.

2. An appliance for testing the sighting device of a gun, consisting ofa collimator,

which comprises a collective lens and a mark place in the focal plane ofthe lens tlllS collimator being adapted to be inserted in the gun withthe collective lens directed 1 an isosceles right-angled simplereflecting prism, which prisms are so combined that the angle ofdeflection of the partial system is 180, and the other partial systemcomprising two isosceles right-angled simple reflecting prisms, whichare so combined that the angle of deflection of the partial system iszero.

RUDOLF STRAUBEL.

Witnesses:

PAUL Kaiieaa, ALFRED Maonnonsz.

